Multiple microphone switching and configuration

ABSTRACT

A mobile communications device contains at least two microphones. One microphone is designated by a selector to provide a voice dominant signal and another microphone is designated to provide a noise or echo dominant signal, for a call or a recording. The selector communicates the designations to a switch that routes the selected microphone signals to the inputs of a processor for voice signal enhancement. The selected voice dominant signal is then enhanced by suppressing ambient noise or canceling echo therein, based on the selected noise or echo dominant signal. The designation of microphones may change at any instant during the call or recording depending on various factors, e.g. based on the quality of the microphone signals. Other embodiments are also described.

FIELD

An embodiment of the invention is generally related to mobile devicesthat have multiple microphones for enhancing an audio signal.

BACKGROUND

Portable handheld electronic devices that have a telephony function,such as the iPhone™ multifunction mobile device by Apple Inc., have abuilt-in or integrated microphone located at a bottom end portion of thedevice which is near the user's mouth when the device is being used as atelephone handset by its user. This microphone captures a voice signalof a near end user which is then transmitted to the other party orparties of a call. The microphone may also be used to record audiosignals for other device features, such as for sound recordings andvideoconferences. However, if ambient noise in the environment orphysical blockage of the microphone interferes with the voice signal ofthe near end user, then the other party of the call may not hear thevoice signal as clearly as he would desire.

SUMMARY

In one embodiment of the invention, a mobile device includes multiplemicrophones (e.g., a microphone array) that work to transmit a voicesignal of a near end user to the other party or parties of a call. Thedevice has a switching and/or configuration process running in an audiosignal processor, that is monitoring the signals being picked up by themicrophones. Upon comparing the signals from the various microphoneswith each other, the process may designate one microphone to provide avoice dominant signal and another microphone may be designated toprovide a noise suppression and/or echo cancellation dominant inputsignal. The voice dominant signal is then enhanced by an uplink voicesignal processor of the device, suppressing ambient noise and echo basedon the noise suppression and/or echo cancellation dominant signal.

The selection of one microphone to provide the voice dominant signal andanother microphone to provide the noise suppression and/or echocancellation dominant signal may be based on one or more factors,determined, for example, by an audio signal processor, accelerometer, oruser input. For example, based on the comparison of audio signals fromeach of the microphones, the microphone that picks up the “best” voicesignal representing a particular near end user (where there may be morethan one such user such as during a conference call) may be selected toprovide the voice dominant signal. In another example, physical blockingof a particular microphone of the device, such as by a person's hand,may cause the audio signal processor to automatically detect such asituation and then switch to another microphone to provide the voicedominant signal (because the voice signal may be more clear as picked upby one of the other microphones of the device). In a further example,microphone selection can be commanded by manual user input thatdesignates which microphone is to provide the voice dominant signal. Itis noted that such microphone selection or switching may occurdynamically, i.e. during a call, or in the midst of a running audioapplication (e.g., during a voice recording), such as when the near enduser shifts the device in her hand causing a microphone to be blocked,or when a near end talker moves from one side of the device to another.

The above summary does not include an exhaustive list of all aspects ofthe present invention. It is contemplated that the invention includesall systems and methods that can be practiced from all suitablecombinations of the various aspects summarized above, as well as thosedisclosed in the Detailed Description below and particularly pointed outin the claims filed with the application. Such combinations may haveparticular advantages not specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “an” or “one” embodiment in this disclosure are not necessarily tothe same embodiment, and such references mean at least one.

FIG. 1 is a block diagram of an example embodiment of a portablehandheld device with multiple microphones for enhancing a voice dominantsignal.

FIG. 2 shows a portable handheld device having multiple microphones forenhancing a voice dominant signal.

FIG. 3 is a flow diagram of a portable handheld device with microphoneswitching capabilities.

FIG. 4 depicts a block diagram of an example, portable handheldmultifunction device in which an embodiment of the invention may beimplemented.

DETAILED DESCRIPTION

In this section, several preferred embodiments of this invention areexplained with reference to the appended drawings. Whenever the shapes,relative positions and other aspects of the parts described in theembodiments are not clearly defined, the scope of the invention is notlimited only to the parts shown, which are meant merely for the purposeof illustration.

FIG. 1 is a block diagram of an example embodiment of a portablehandheld device with multiple microphones for enhancing a voice dominantsignal. The device may be an iPhone™ device by Apple Inc. of Cupertino,Calif. Alternatively, it could be another portable handheldmulti-function mobile electronic device or smart phone that has audiorecording and/or voice telephony capacities. The device may have afixed, single piece housing like the iPhone™ device, or it may have amovable, multi-piece housing such as a clamshell design or slidingkeypad. The device may also have a display screen which can be used todisplay typical smart phone features such as visual voicemail, webbrowsing, email, digital camera photos, and others.

The device includes an antenna 105 that receives and transmits signalsin conjunction with a radio frequency transceiver 110 for a wirelesscall between a near end user of the device and another party, the farend user. Two main channels may be implemented for the processing ofaudio signals associated with a call, namely an uplink channel processorand a downlink channel processor, both of which may be implemented inpart by a coder/decoder integrated circuit device, CODEC 175. Thedownlink channel processor may be responsible for demodulating andenhancing the audio signals received from the far end user over awireless communications network 100. For example, when the far end userspeaks, his voice signal is received from the network 100 by the RFtransceiver 110 and antenna 105, and then demodulated and processed bythe downlink channel processor for listening by the near end user of thedevice through any one of several ways. During a call, the device mayoperate in one of at least three modes: handset mode, speaker mode, andheadset mode (including both wired and wireless, e.g. Bluetooth, headsetimplementations). A switch 170 thus routes the downlink audio signal toa loudspeaker 165, earpiece speaker 145, or a headset 155 (a wired orwireless headset) based on the mode of the call.

The uplink channel processor supports the transmission of audio signalsoriginating from the near end user of the device acquired by one or moreof microphones 120, 121, 122, 123 and sent to the far end user over awireless communications network. In other words, when the near end userspeaks, his voice signal is processed by the uplink channel processorfor enhancing quality and then modulated onto a carrier signal fortransmission by the antenna 105 to the other party.

In the example shown in FIG. 1, the device has four microphones, all ofwhich may be integrated in a device housing (together with most of theother components depicted). In general, however, the concepts here areapplicable to devices that have two or more microphones. An audiodigital signal processor 132 monitors (to compare or analyze) theavailable microphone signals and provides the results of its analysis toa selector 129. The latter on that basis configures a switch 130 to ineffect select one of the four microphones 120, 121, 122, 123 to act asthe “primary” microphone, to provide a voice dominant signal (based onthe audio signal picked up by each of the four microphones 120, 121,122, 123). The switch 130 may route the selected microphone signals to avoice dominant signal input of the CODEC 175 and a noise and/or echodominant signal input of a controller 180. The selector 129 makes thedecision to select one or more of the remaining microphones to act asthe “secondary” microphone(s) (or “tertiary,” etc.) to also provide anoise suppression and/or echo cancellation dominant signal, which isused to enhance the voice dominant signal of the primary microphonethrough noise suppression and/or echo cancellation. Using separatemicrophones to provide the voice dominant signal and to provide thenoise/echo cancellation dominant signal may be superior to using asingle microphone to derive both signals, because the separatemicrophones, by virtue of being located at different places in thedevice housing, may provide a better representation of the sound wavesthat are incident on the device housing. A combination of the factorsdescribed below may assist the selector 129 in determining whichmicrophones to select for providing and enhancing the voice dominantsignal.

To continue with an example, one scenario that would influence thequality of a microphone signal is when a user inadvertently blocks theassociated microphone with his hand, e.g. see FIG. 2, where mic 2 andmic 3 are physically blocked. In this case, an analysis of the signalsfrom these physically blocked microphones may indicate that they are notideal selections for providing a voice dominant signal. However, itshould be noted that the microphone that picks up the highest powered orloudest signal is not necessarily the appropriate choice for providingthe voice dominant signal. Various factors involving signal-to-noiseratio, total harmonic distortion, crosstalk, and side tone may be takeninto consideration when evaluating which microphone's signal should beused as the voice dominant signal.

Another instance of automatic microphone switching may occur whenchanging from handset mode to speakerphone mode, and vice-versa. Thus,in addition to the analysis and comparison of the microphone signalsbetween each other, the decision to select a different microphone duringa call may also be influenced by the mere fact of a change betweenhandset and speakerphone modes.

In another embodiment, a touchscreen 230, see FIG. 2 (or other mechanismfor receiving manual input from the near end user), may influence whichmicrophones are selected by the switch 130 to provide the voice dominantsignal and echo/noise dominant signal. A user of the device may actuatea virtual button on the touchscreen (or a physical button on the device)to provide a direct indication of which microphone the user would liketo use to pick up the voice dominant signal. For example, if the user isholding the device up to video record a subject in a recorded interviewsession, the user may press a predetermined button that is associatedwith mic 2 (se FIG. 2) which may be the one that is most directly facingthe interviewee. The near end user may then switch to another microphonethat is facing himself (the interviewer) when he is speaking.

In yet another embodiment, the device implements audio tracking or audiobeam forming capability using its microphones, to identify theparticular “theta” (angle) at which a target speaker is located, bymeasuring for the maximum audio signal picked up for the target speaker.Thus, as a target speaker is moving around while talking, thetracking/beam forming capability may actively track the strongest signalby switching amongst multiple microphones situated in a microphone arrayso as to always select the “best” of the available microphone signals asthe voice dominant signal.

In a multi-party audio session such as a conference call or a grouprecording, multiple microphones and multiple cameras can be used tovisually and audibly record or send an uplink voice call signal of twonear end speakers to a third (far end) party. Here, both near end usersmay be speaking at the same time, which may require double themicrophone selection aspects (e.g., two microphones may be selected topick up voice dominant signals of two users) and the audio signals maybe either mixed in a full duplex manner or separated in a half-duplexmode where the signals take turns.

In a further embodiment, an accelerometer 134 may influence whichmicrophones are selected to provide the voice dominant signal and whichare used to enhance the voice dominant signal. For example, movement orre-positioning of the device can be detected using the accelerometer134, to indicate that certain microphones positioned at certain parts ofthe device are more appropriate to use in a particular situation.

Although the switch 130 is symbolized by a rotary-type switch symbol,its practical implementation may be entirely digital. In other words,the switch 130 may provide the microphone signals as digital streams,through several digital outputs. The switch may be a software andhardware implementation that performs “software” routing by, forexample, providing different pointers to the different microphonestreams that are retrieved from memory. The digital outputs may bemapped to several digital inputs of the uplink voice processor as shownin FIG. 1 that selects multiple microphones based on the above factorsand/or commands. For example, these selected signals may be input to theCODEC 175, which refers to a coder-decoder that processes (e.g., decodesor decompresses) an input, coded, voice dominant stream. An echo/noisecancellation controller 180 refines the voice dominant signal receivedfrom the CODEC 175 by suppressing noise and canceling echo with theassistance of one or more signals from the other selected microphones.The echo/noise cancellation controller 180 may also operate on adownlink voice signal. Accordingly, the echo/noise cancellationcontroller 180 may be relevant to both near end echo and the far endecho. Near end echo refers to the far end user hearing his own echobecause the near end user is operating the device in speaker mode. Farend echo refers to echo from the network or line echo. The output of theecho/noise cancellation controller 180 provides an, enhanced voicesignal that is sent to the radio frequency transceiver 110. Thecontroller 180 also has an output that provides control information orfeedback to the selector 129 regarding the enhancement of the voicedominant signal.

Turning now to FIG. 2, this figure depicts an example embodiment of aportable handheld device 200 having multiple microphones 120, 121, 122,123 for enhancing a voice dominant signal of a near end user. In thisillustration, the near end user is holding the device 200 in her hand.

The device 200 includes various capabilities to enable the user toaccess features involving, for example, calls, text messages, voicemail,e-mail, the Internet, scheduling, photos, and music as shown on thedisplay screen 230. This figure depicts a first microphone 120 locatedaway from the earpiece receiver speaker 145 so that the voice signal ofthe near end user may be more easily received when holding the device200 to the user's ear. Three additional microphones 121, 122, 123 arelocated at the side of the device 200, but it should be recognized thatthere may be a greater or fewer number of microphones located anywhereon the device 200.

For applications that involve a microphone, such as a telephone call,audio recording, or videoconference, each of the four microphones 120,121, 122, 123 may pick up a near end audio signal. One microphone may beselected as the primary microphone to provide a voice dominant signaland another microphone may be selected as the secondary microphone toprovide a noise suppression and/or echo cancellation dominant signal.This selection may change dynamically or switch during a call or audiorecording, depending on one or more factors, including a comparison ofthe signals from these four microphones 120, 121, 122, 123 made by theaudio digital signal processor 132 (see FIG. 1), a current call handlingmode of the device 200 (e.g., handset mode or speakerphone mode), anduser input received via the touch screen 230. In one example, based onthe comparison of audio signals from each of the microphones, themicrophone that picks up the most optimal voice signal may be selectedto provide that signal. In another example, a physical blocking of aparticular microphone of the device, such as by a person's hand, maycause the device not to select that microphone to provide the voicedominant signal because the voice signal may be clearer as read by oneof the other microphones of the device. In addition, microphoneselection can be commanded by user input that designates whichmicrophone provides the voice dominant signal. Furthermore, microphonescan be selected based on a mode of the device, e.g., to select the firstmicrophone 120 as the primary microphone or voice dominant signalprovider when in handset mode and one of the other microphones 121, 122,123 as the primary microphone or voice dominant signal provider when inspeakerphone mode. In the case that more than two microphones areprovided on a device, the remaining microphones may either be ignored orturned off with respect to enhancing the voice dominant signal or theymay be used to further assist in enhancing the voice dominant signal.

It is noted that such microphone selection may dynamically change duringthe call or in the midst of a running application (e.g., during a voicerecording). For instance, if a near end user is speaking on the phoneand shifts his hand over the phone to hold it in a different position,he may inadvertently block the microphone selected as the primarymicrophone that provides the voice dominant signal with his hand. Inthis situation, the device may sense that this microphone no longerprovides the most optimal voice dominant signal as compared to anothermicrophone and therefore dynamically switches its selection to the othermicrophone, as the primary microphone to provide the voice dominantsignal during the call.

Proceeding to the next figure, FIG. 3 is a flow diagram of a portablehandheld device with microphone switching capabilities. The device usesmultiple microphones to enhance a voice dominant signal by suppressingambient noise and/or echo.

In this example embodiment, the device initially receives audio signalsfrom all microphones of the device (operation 310). The device has atleast two microphones located at various locations on the device. Eachof the signals is then compared with each other to determine whichmicrophone provides the most optimal voice dominant signal (operation320). One of the microphones is then selected as the primary microphoneto provide the voice dominant signal (operation 330). In the case of twomicrophones on the device, the remaining microphone is, by default, thesecondary microphone to provide the noise suppression and/or echocancellation dominant signal (operation 340). If there are more than twomicrophones on the device, then one or more of the other remainingmicrophones may be selected as the secondary, tertiary, etc. microphoneto assist with ambient noise and echo cancellation to enhance the voicedominant signal (operation 350). This selection may be informed byfeedback from the noise/echo cancellation controller 180 (see FIG. 1),through, for example, a trial and error procedure that applies signalsfrom the remaining microphones to enhance the voice dominant signal andevaluates them to select the one that is likely to result in the “best”enhancement to the voice dominant signal. The voice dominant signal ofthe primary microphone is then enhanced by performing noise suppressionand/or echo cancellation with the assistance of the selected one or moreof the other microphones (operation 360).

It is noted that other embodiments of selecting a microphone for thevoice dominant signal exist. For example, in the case of user inputswitching, the device need not receive and compare audio signals of allmicrophones before selecting a microphone as the primary microphone.Rather, microphone selection would occur according to user command froma physical button, a virtual button on a touch screen, etc.

FIG. 4 depicts a block diagram of an example, portable handheldmultifunction device 200 in which an embodiment of the invention may beimplemented. The device 200 has a processor 704 that executesinstructions to carry out operations associated with the device 200. Theinstructions may be retrieved from memory 720 and, when executed,control the reception and manipulation of input and output data betweenvarious components of device 200. Although not shown, the memory 720 maystore an operating system program that is executed by the processor 704,and one or more application programs are said to run on top of theoperating system to perform different functions described below. Theaccelerometer 134 provides an indication of the position or movement ofthe device. The screen 230 displays a graphical user interface (GUI)that allows a user of the device 200 to interact with variousapplication programs running in the device 200. The GUI displays iconsor graphical images that represent application programs, files, andtheir associated commands on the screen 230. These may include windows,fields, dialog boxes, menus, buttons, cursors, scrollbars, etc. The usercan select from these graphical images or objects to initiate thefunctions associated therewith.

In one embodiment, the screen 230 is a touch screen that also acts as aninput device, to transfer data from the outside world into the device200. This input is received via, for example, the user's finger touchingthe surface of the screen 230, but it may also be received via physicalbuttons on the device 200. When the screen is powered on, touch inputsmay be received and when the screen is powered off, touch inputs may notbe received.

Still referring to FIG. 4, the device 200 may operate in a mobiletelephone mode. This is enabled by the following components of thedevice 200. An integrated antenna 105 that is driven and sensed by RFcircuitry 110 is used to transmit and receive cellular networkcommunication signals from a nearby base station, or wireless local areanetwork signals from a wireless access point or router (e.g., to enablewireless voice over Internet Protocol, VOIP, calls) (not shown). Amobile phone application 724 executed by the processor 704 presentsmobile telephony options on the screen 230 for the user, such as avirtual telephone keypad with call and end buttons. The mobile phoneapplication 724 also controls at a high level the two-way conversationin a typical mobile telephone call, by directing a speech signal fromone or more built-in microphones 120, 121, 122, 123 to the uplink voicesignal processor which then feeds the RF circuitry, while at the sametime directs a speech signal from the other side of the conversation tothe downlink voice signal processor an then through the receiver or earspeaker 145 in handset mode, and the loudspeaker 165 in speaker mode.The mobile phone application 724 also responds to the user's selectionof the receiver volume, by detecting actuation of the physical volumebutton 716. Although not shown, the processor 704 may include a cellularbase band processor that is responsible for much of the downlink anduplink digital audio signal processing functions and cellular networkprotocol signaling associated with a cellular phone call, includingencoding and decoding the voice signals of the participants to theconversation.

The device 200 may be placed in either handset mode or speaker mode fortelephone calls, in response to, for example, the user actuating aphysical menu button 707 and then selecting an appropriate icon on thedisplay device of the screen 230. In either telephone mode, the mobilephone application 724 may control loudness of the downlink signal, basedon a detected actuation or position of the physical volume button 716.

Some of the elements described in FIGS. 1 and 2 may be implemented asinstructions stored in memory 720 that program the processor 704. Themicrophone switching control logic that is responsible for the decisionthat selects the microphones used for the voice dominant signal and forthe noise suppression and/or echo cancellation dominant signal may beimplemented in a microphone selector and switch module 732. The audioDSP 132, which compares the audio signals picked up by each of themicrophones may be implemented in a signal processing module 728. ACODEC module 726 may perform the purely digital aspects of the downlinkand uplink voice signal processing functions of the CODEC 175, and thenoise/echo cancellation controller 180 may be implemented in anoise/echo cancellation module 730. Other combinations of hardware andsoftware that can perform the functions of these elements in a mobiledevice are possible.

An embodiment of the invention may be a machine-readable medium havingstored thereon instructions which program a processor to perform some ofthe operations described above. In other embodiments, some of theseoperations might be performed by specific hardware components thatcontain hardwired logic. Those operations might alternatively beperformed by any combination of programmed computer components andcustom hardware components.

A machine-readable medium may include any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer), not limited to Compact Disc Read-Only Memory (CD-ROM),Read-Only Memory (ROM), Random Access Memory (RAM), and ErasableProgrammable Read-Only Memory (EPROM).

In the foregoing specification, the invention has been described withreference to specific embodiments thereof. It will, however, be evidentthat various modifications and changes can be made thereto withoutdeparting from the broader spirit and scope of the invention as setforth in the appended claims. For example, the microphone switchingcapabilities described above, used to enhance a voice dominant signal byapplication of noise suppression and/or echo cancellation, may also beapplied in applications such as audio or video recordings, rather thanongoing telephone calls. In that case, referring now to FIG. 4, adigital media player application module may be added that is stored inthe memory 720 for enabling the user of the device 200 to manage therecording. The specification and drawings are, accordingly, to beregarded in an illustrative rather than a restrictive sense.

1. An apparatus comprising: a communications device housing havingintegrated therein: an uplink channel processor to provide an uplinkvoice signal for a call by enhancing a voice dominant input signal usingan echo or noise dominant input signal; a downlink channel processor toreceive a downlink voice signal for the call; a plurality ofmicrophones; a switch to couple (a) a microphone signal, that isselectable from each of the plurality of microphones, into a voicedominant input of the uplink channel processor, and (b) a furthermicrophone signal, selectable from each of the plurality of microphones,into a noise and/or echo dominant input of the uplink channel processor;and a selector to dynamically control the switch during the call tochange the coupling of the microphone signals wherein the selector is tochange coupling of the voice dominant input and the noise and/or echodominant input, based on a current call handling mode of the apparatus,the current call handling mode being one of handset mode andspeakerphone mode.
 2. The apparatus of claim 1, wherein the switch is tocouple an additional microphone signal, selectable from each of theplurality of microphones, into a supplementary input of the uplinkchannel processor for enhancing the voice dominant input signal.
 3. Theapparatus of claim 1, wherein the selector is to change coupling of oneof the voice dominant input or the noise and/or echo dominant inputbased on an analysis of microphone signals from the plurality ofmicrophones.
 4. The apparatus of claim 3, wherein the selector is tochange said coupling of one of the voice dominant input or the noiseand/or echo dominant input in response to one micro hone signal having areduced signal to noise ratio as compared to another one of themicrophone signals.
 5. The apparatus of claim 1, wherein the selector isto change coupling of one of the voice dominant input or the noiseand/or echo dominant input based on a position of the apparatus detectedby an accelerometer.
 6. The apparatus of claim 1, wherein at least twomicrophones of the plurality of microphones are not positioned adjacentto each other.
 7. A machine-implemented method comprising the followingoperations performed in a communications device during a recordingsession or a call: analyzing signals from a plurality of microphones;switching a first coupling of a microphone signal between the pluralityof microphones and a voice dominant input based on the analysis of thesignals from the plurality of microphones; switching a second couplingof a further microphone signal between the plurality of microphones anda noise or echo dominant input based on the analysis of the signals fromthe plurality of microphones; and enhancing the microphone signal thatis coupled to the voice dominant input, by suppressing ambient noiseand/or canceling echo based on the microphone signal that is coupled tothe noise or echo dominant input, wherein one of said switching a firstcoupling and a second coupling is based on a current call handling modeof operation of the communications device being one of handset mode andspeakerphone mode.
 8. The machine-implemented method of claim 7, whereinsaid switching a first coupling is in response to one microphone havinga reduced signal-to-noise ratio as compared to another microphone in theplurality of microphones.
 9. The machine-implemented method of claim 7,wherein said switching a second coupling is in response to onemicrophone having a reduced signal-to-noise ratio as compared to anothermicrophone in the plurality of microphones.
 10. A telephony devicecomprising: a housing having a plurality of microphones; a selector todynamically select, during a sound recording or sound communication, onemicrophone of the plurality of microphones for a voice dominant inputand another microphone of the plurality of microphones for a noise orecho dominant input; a switch coupled to the selector and to theplurality of microphones, to route signals from the selected microphonesto said voice dominant and noise or echo dominant inputs; and aprocessing component to enhance the signal at the voice dominant inputbased on the signal at the noise or echo dominant input wherein theplurality of microphones are more than two microphones and wherein theselector's dynamic control of the switch is informed through a trial anderror procedure that (a) applies microphone signals, other than the onecoupled to the voice dominant input by the switch, to enhance themicrophone signal that is coupled to the voice dominant input and (b)evaluates the applied microphone signals to select one that is mostlikely to enhance the microphone signal that is coupled to the voicedominant input.
 11. The telephony device of claim 10, wherein outputsignals of unselected ones of the plurality of microphones are ignoredby the processing component while enhancing the voice dominant inputsignal.
 12. The telephony device of claim 10, wherein the selector is tochange a selection of the one microphone or the another microphoneduring the sound recording or sound communication.
 13. The telephonydevice of claim 10, wherein the selection of the one microphone inhandset mode differs from the selection of the one microphone inspeakerphone mode.
 14. The telephony device of claim 10, wherein theprocessing component is to use each of the plurality of microphones toactively track a voice of a person in the sound recording or soundcommunication.
 15. The method of claim 7 wherein output signals ofunselected ones of the plurality of microphones are ignored whileenhancing the microphone signal that is coupled to the voice dominantinput.
 16. The method of claim 7 wherein the plurality of microphonesare more than two microphones and wherein said switching a secondcoupling is informed through a trial and error procedure that (a)applies microphone signals, from the microphones other than the oneassociated with the first coupling, to enhance the microphone signalthat is coupled to the voice dominant input and (b) evaluates theapplied microphone signals to select one that is most likely to enhancethe microphone signal that is coupled to the voice dominant input. 17.The telephony device of claim 10, wherein the selector is to select theone microphone and the another microphone based on information from anaccelerometer.
 18. The apparatus of claim 1 wherein the selector is tochange the coupling of the voice dominant input in response to onemicrophone signal having reduced signal-to-noise ratio as compared toanother.
 19. The telephony device of claim 10, wherein the soundrecording or sound communication is a video recording.
 20. The telephonydevice of claim 10, wherein the sound recording or sound communicationis a video conference call.